Currently, projectors have been widely used as image projection devices to project images on projection screens. Generally, a projector displays a color image by converging light emitted from a light source onto a spatial light modulator such as a DMD (Digital Micromirror Device) or a Lcos.
In recent years, a projection system in which a distance between a projector and a screen is 50 cm has been developed, which can achieve image projection display of a screen larger than 100 inches. In the projection system, since the projection screen fixed to a wall is arranged to be closer to a projector including a light source device, it is possible to overcome limitation of installation space, so that an image projection display of a large screen larger than 100 inches can be achieved within a short distance of 50 cm.